1. Field of the Invention
The present invention relates to a device cooperation system in which plural devices connected via a network take partial charge of providing functions of the devices.
2. Description of the Related Art
There is known a processing format referred to as device cooperation, by which plural devices connected in a network cooperate with each other to execute a single job. Device cooperation means, for example, that plural devices take partial charge of providing functions necessary for a single job constituted by a series of processes starting from input to output.
FIG. 1 illustrates an example of executing a job by device cooperation. An MFP (multifunction peripheral) 1 and an MFP 2 are connected to each other via a network. The MFP 1 does not have a fax function, but the MFP 2 has a fax function. A user Q wants to transmit image data by fax, but because the MFP 1 does not have a fax function, the user Q uses the MFP 1 to scan an original document by the scanner function, and use the fax function of the MFP 2 to transmit the image data by fax.
FIG. 2 illustrates another example of executing a job by device cooperation. Both the MFP 1 and the MFP 2 have a printing function. The user Q wants to print out plural copies of the image data. The printing operation can be done with only the MFP 1; however, by having the MFP 2 take partial charge of the printing operation, the printing operation can be completed quickly. The user Q may operate the MFP 1 to scan the original document with the scanning function, and transmit the image data and print conditions to the MFP 2, so that the printing operation is shared by the MFP 1 and the MFP 2.
Incidentally, MFPs are shared by many users in offices. For this reason, conventionally, there are MFPs having a function of setting the upper limit frequency (upper limit usage amount) of copying and printing for each user, so that a particular person does not use the copying and printing functions unlimitedly (see, for example, Patent Document 1). Patent document 1 discloses the following service execution device. The service execution device transmits, to a server, a usage request for authentication information and a usage request of a scheduled number of sheets to be used. When the scheduled number of sheets to be used requested to the server is less than or equal the number of sheets that the user can use, the service execution device executes a job based on user instructions with the scheduled number of sheets to be used set as the upper limit.
However, in Patent Document 1, although it is possible to authenticate a user by a server so that authentication for plural devices can be performed at once, the user Q cannot be authenticated unless there is a server. That is to say, in a case where the respective devices are to authenticate the user instead of the server, no consideration is made as to how the MFP 2 authenticates the user Q. For example, when the user Q does not have the authority to use the MFP 2, the user Q is not to be allowed to use the MFP 2 in device cooperation. Furthermore, even if the user Q has the authority to use the MFP 2, if the MFP 2 cannot authenticate the user Q, it is not possible to count or limit the usage amount of the user Q. Accordingly, in the conventional device cooperation system, the usage amount of the user cannot be accurately limited when device cooperation is performed.    Patent Document 1: Japanese Laid-Open Patent Publication No. 2010-074431